# Define here the models for your spider middleware
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/spider-middleware.html

import execjs
from scrapy import signals
import os
import json
from collections.abc import Mapping
from .commons.utils import generate_headers
from w3lib.http import headers_dict_to_raw
from scrapy.utils.datatypes import CaseInsensitiveDict, CaselessDict
from scrapy.utils.python import to_unicode




class ScrapyServiceSpiderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, or item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Request or item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info("Spider opened: %s" % spider.name)


class ScrapyServiceDownloaderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None


    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        # print(response)
        # spider.logger.info(response.text)
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        # spider.logger.error(exception)
        pass

    def spider_opened(self, spider):
        spider.logger.info("Spider opened: %s" % spider.name)
class XiaoHongShuMiddleware:
    def __init__(self):
        # 初始化中间件
        pass

    @classmethod
    def from_crawler(cls, crawler):
        # 从 Crawler 对象中获取配置信息
        middleware = cls()
        crawler.signals.connect(middleware.spider_opened, signal=signals.spider_opened)
        return middleware

    def spider_opened(self, spider):
        # 当爬虫被打开时执行的操作
        spider.logger.info('XiaoHongShuMiddleware opened: %s' % spider.name)

    def process_request(self, request, spider):
        # 处理请求，动态生成请求头
        base_url = 'https://edith.xiaohongshu.com'
        api = request.meta.get('api')
        data = request.meta.get('data')
        if api:
            url = f"{base_url}{api}"
            request._set_url(url)  # 修改请求的URL
            spider.logger.debug('Modified URL: %s' % url)
        if request.method == 'POST':
            if data:
                json_data = json.dumps(data, separators=(',', ':'), ensure_ascii=False).encode('utf-8')
                request._set_body(json_data)  # 修改请求的Body
                # spider.logger.debug('Modified POST data: %s' % json_data)
        headers,cookies = generate_headers(api, data)
        if headers:
            request.headers.update(headers)  # 添加动态生成的请求头
            request.cookies.update(cookies)
            # print(request.body)
            # spider.logger.debug('Added dynamic headers: %s' % dynamic_header)


